Enhanced lignin hydrogenolysis through synergy-induced bimetallic NiCu catalyst for chemocatalytic production of aromatic monomers

Abstract

Bimetallic catalysts are widely favored for catalytic reactions due to their superior performance and cost-effectiveness. This study delves into the utilization of a non-noble bimetallic catalyst, NiCu/C, in the hydrogenolysis of lignin to yield valuable aromatic monomers. Under optimized temperature, this catalyst achieves an impressive 92.4% conversion of lignin into liquid products, yielding 17.7 wt% of monomers. These results outperform the performance of the monometallic catalysts (Ni/C and Cu/C). To gain insight into the detailed catalytic reaction mechanism, the catalysts underwent advanced characterization techniques such as N2 physisorption, XRD, XPS, H2-TPR, and TEM, which provided information on their textural properties, structure, oxidation states, and more. The findings clearly highlight the significant role played by the synergistic interaction between Ni and Cu metallic species in bolstering the H2 adsorption capacity, thereby resulting in elevated catalytic hydrogenolysis activity. Characterization of the lignin hydrogenolysis products was also conducted to understand the effects of bimetallic and monometallic catalysts. These findings align with the catalyst characterizations and lend further support to the significant enhancement in catalytic hydrogenolysis attributed to the synergistic impact of the NiCu/C catalyst.